Blowout preventer



Nov. 2, 1965 H. ALLEN 3,215,393

BLOWOUT PREVENTER Original Filed Dec. 15, 1958 6 Sheets-Sheet 1 FIG.

a Q Q a 49 Herberz /4//e/7 INVENTOR.

Nov. 2, 1965 ALLEN BLOWOUT PREVENTER 6 Sheets-Sheet 2 Original Filed Dec. 15, 1958 INVENTOR.

Nov. 2, 1965 H. ALLEN 3,215,393

BLOWOUT PREVENTER Original Filed Dec. 15, 1958 6 Sheets-Sheet 3 FIG 44 7 \\\\\\\\III.

f/erber I /4//e/7 INVENTOR.

By M,M/ m

Nov. 2, 1965 H. ALLEN BLOWOUT PREVENTER 6 Sheets-Sheet 4 Original Filed Dec. 15, 1958 fle/uer A//e/7 INVENTOR. By M, M W 6 ATTORNEYS ALLEN 3,215,393

6 Sheets-Sheet 5 BLOWOUT PREVENTER Herbert /4//e/7 INVENTOR.

BY I %;M j r ATTO/F/VEVJ Nov. 2, 1965 Original Filed Dec. 15. 1958 Nov. 2, 1965 H. ALLEN 3,215,393

BLOWOUT PREVEN'IER Original Filed Dec. 15, 1958 6 Sheets-Sheet 6 INVENTOR.

BY M W (p '6 Heruer 7 /4//e/7 gig...

Illlllllll'lllllllllllllillllilillllllllllllllllllll'll Ill IIIIIIJI H IH s lllllllilllllllll. hi... \h 1 E s I-EJWH ATTO/Q/VEVJ United States Patent l 3,215,393 BLGWDUT PREVENTER Herbert Allen, Houston, Tex., assignor to Cameron Iron Works, Inc., Houston, Tex.

@riginal application Dec. 5, 1958, Ser. No. 778,342, now Patent No. 3,132,662, dated May 12, 1964. Divided and this application Nov. 15, 1963, Ser. No. 323,949

1 Claim. (Cl. 251-4) This application is a division of my co-pending application Serial No. 778,342, filed December 5, 1958, entitled, Valve Apparatus for use as a Blowout Preventer or the Like, and now Patent No. 3,132,662, which was in turn a continuation-in-part of my application Serial No. 673,299, filed July 22,, 1957, entitled, Valve Apparatus, now abandoned.

This invention relates generally to blowout preventers and, more particularly to improvements in blowout preventers of the type in which the rams are moved between opened and closed positions in the general manner disclosed in US. Patent No. 3,132,662.

In the drilling and completion of oil and gas wells, it is frequently necessary to seal off the well at the wellhead and, if a pipe is disposed within the well, to seal about the pipe. The apparatus commonly employed for this purpose is known as a blowout preventer and comprises a body disposable at the well head having a bore therethrough to form a continuation of the well. Two or more rams are movable longitudinally within guide- Ways in the body intersecting the bore between positions retracted from the bore for opening same and positions extending across the bore into engagement with one another for closing the bore. The inner ends of the rams may be formed to fit about and seal with a pipe within the bore therethrough.

The actuators for reciprocating the rams between opened and closed positions are generally connected thereto by a rod on the ram sealably reciprocable within openings through bonnets which close the guideways for the rams in the body. Thus, the force for closing the rams must act against a force due to well pressure acting against the crosssectional area of the rod. It is also conventional to provide screws each for engaging a ram or a part thereof, such as the aforementioned piston, to lock them in closed position. These screws may be carried on the bonnets for selective manipulation into or out of locking position.

However, in the blowout preventer shown and described in the above-mentioned patent, each ram is moved between opened and closed positions by an interial crank arm connected to a shaft mounted on the body for rotation about an axis transverse to the direction of movement of the ram. More particularly, the shaft extends through the side of the preventer body for connection to the actuator. This construction reduces the power requirements of the preventer by eliminating the piston effect of the conventional reciprocating stem and also prevents dirt and other debris from being dragged through the seals as is common in the case of a reciprocating stern.

An object of this invention is to provide a blowout preventer of the type above described having an actuator which is particularly well suited for cooperation with the laterally extending shafts in moving the rams between opened and closed positions.

Other objects, advantages and features of this invention will be apparent to one skilled in the art upon a consideration of the written specification, the attached claim and the annexed drawings.

These and other objects are accomplished, in accordance with the illustrated embodiments of the invention, by a blowout preventer of the type shown in the patent 3,Zl5,3% Patented Nov. 2, 1965 ice having another crank arm on the exterior portion of each transverse shaft together with and actuator having extendible and retractable members pivotally supported on the exterior crank arms for rotating the shafts in directions to move the rams between opened and closed positions. More particularly, the actuator is removably supported on the exterior crank arms to permit its replacement separately of the interior crank arm actuators, and thereby adapt the preventer to different power requirements or permit the use of other types of actuators.

In the drawings, wherein like reference characters are used throughout to designate like parts:

FIG. 1 is an elevational view of a blowout preventer constructed in accordance with the present invention;

FIG. 2 is a right end view of the preventer of FIG. 1;

FIGS. 3 and 4 are perspective views of the rams of the preventer and parts of the actuator therefor, removed from the preventer and in opened and closed positions, respectively;

FIG. 5 is a cross-sectional view of the preventer on an enlarged scale and as seen along broken lines 5-5 of FIG. 1;

FIG. 6 is a longitudinal sectional view of one end of the preventer and showing a ram thereof in closed position;

FIG. 7 is a side view, partly in section, of the actuator of FIGS. 1 and 2 and the external crank arms when the rams are in opened position;

FIG. 8 is a cross-sectional view of the actuator taken substantially along broken lines 8-8 of FIG. 7;

FIG. 9 is another cross-sectional view of the actuator taken substantially along broken lines 99 of FIG. 7;

FIG. 10 is a longitudinal sectional view of an alternative form of the actuator with the external crank arms also arranged to dispose the rams in opened position;

FIG. 11 is an enlarged cross-sectional view of the actuator of FIG. 10 taken substantially along broken lines 11-11 of FIG. 10;

FIG. 12 is a longitudinal sectional View, as seen from the top, of the next-described form of actuator; and

FIG. 13 is a longitudinal sectional view, similar to FIG. 10, of still another form of actuator.

Referring now to the above-described drawings, the blowout preventer shown in FIGS. 1 and 2 comprises a body 20 having a bore 21 therethrough (see FIG. 6) and guideways 22 therein intersecting opposite sides of the bore. A bonnet 23 is hingedly connected at 24 (see FIG. 2) to each opposite end of the body 2t? for swinging between positions closing the outer end of each guideway 22 and opening same. A sealing element is received within an annular groove 23a in the inside surface of each bonnet for sealing about the guideway 22 in each end of the body. In its closed position each bonnet 23 may be secured to the body by means of bolts 25. Each of the top and bottom of the body is provided with a flange 26 for connection with another wellhead fitting (not shown) having a bore therethrough adapted to form a continuation of the bore 21. As previously noted, and as will be understood more fully from the description to follow, the body is of such simplified construction, both internally and externally, that it may be forged.

A ram 27 is closely fittable within each of the guideways 22 for movement between a closed position in which its inner end is extended across the bore 21 (FIG. 6) for engagement with the inner end of the ram movable within the opposite guideway, as shown in FIG. 4, and an open position in which its inner end is retracted from the bore so as to provide a full opening therethrough. Each such ram is provided with resilient sealing means 28, such as rubber, having a portion 29 extending laterally across and protruding from the inner end of the ram for sealing engagement with a similar portion of the opposite ram, portions 30 at opposite sides of the ram for sealing engagement with opposite sides of its guideway, and a still further portion 31 extending laterally across the upper side of the ram between the rearward ends of portions 30 for sealing engagement with the top or upper side of each guideway 22 in both the opened and closed positions of the ram. In this manner, the rams close off the bore 21 when they are moved into engagement with one another. When there is no pipe disposed within the bore of the blowout preventer body, the portion 29 of the sealing means may be flat, as shown in FIG. 3. n the other hand, when the rams are to seal about a pipe 32 within the bore, the sealing portion 29 thereof is provided with a groove 33 (FIG. 6) having a radius adapted to fit closely about one half of the pipe.

As best shown in FIG. 6, the bottom or lower side of each of the guideways 22 is provided with a longitudinal recess or slot 34 which provides access for the fluid within the bore 21 beneath the closed rams to the outer ends of the rams. Thus, the force due to the pressure of this fluid, which will be well fluid in the case of the blowout preventer, will urge the rams toward closed position. Since, in the closed position of the rams, the inner ends thereof are sealed with respect to one another along portions 29, there will be a pressure differential acting across the rams which will aid in maintaining them in closed position.

A shaft 35 is mounted on the body on each side of the bore 21 for rotation about an axis offset from the guideway 22 and transverse to the direction of movement of the ram 27. A crank arm 36 on each shaft is provided with rollers 37 on one end thereof which are receivable within a slot 38 in a ram for moving said ram longitudinally within its guideway in response to rotation of the shaft. More particularly, the portion of crank arm 36 intermediate the shaft 35 and a shaft 39 which mounts the rollers 37 is swingable within recess 34 as well as portion 40 of the slot 38 which opens onto the outer end of the ram. The slot 38 in each ram also opens to the lower side or bottom thereof to permit the rollers 37 on the end of the crank arm 36 to swing through the open end of the slot and out of engagement with the ram so the ram may be removed from the outer end of the guideway as described in Patent No. 3,132,662. Obviously, when the crank arm is swung into this position, the rollers are disposed in a position for easy entry into the slot as the ram is moved back into the guideway.

In order to facilitate disengagement of each crank arm from its ram, each recess 34 of the body is relieved at 41 beneath the shaft 35; and the lower side or bottom of each of the rams is provided with a longitudinal slot 42 extending from the slot 38 to the inner end of the ram. Each ram 27 is movable to its open position with the outer end of the guideway 22 closed by the bonnet 23. However, upon release of the bolts 25 and swinging of the bonnet 23 about its hinge 24, the shaft 35 may be swung in a counterclockwise direction so as to move the ram from its closed position to another position in which its inner end is further retracted from the bore 21 and its outer end projects from the open outer end of the guideway a sufiicient distance to facilitate its manual removal to a position completely out of the guideway.

As best shown in FIG. the shaft 35 is sealably received within opposite sides of the ram body 20. Since there is no piston effect the only force which is to be overcome by the actuator during movement of the ram into closed position is that due to friction. One end of the shaft 35 extends through one side of the body for connection with the actuator which includes means for rotating the shaft as will be described hereinafter.

Each crank arm 36 is splined at 43 to its shaft 35, and each shaft is carried for rotation but maintained against longitudinal movement by means of bearings 44 surrounding the shaft on opposite sides of the splined portion thereof and received within openings in each side of the body. The bearings 44 are, in turn, held against outwardly facing shoulders 44a in the body openings by means of a sealing assembly which includes an annular ring 45 disposed about the shaft adjacent the outer end of the bearing, an annular packing 46 about the shaft adjacent the ring, and a gland nut 47 for the packing. As shown in FIG. 5, each gland nut is held tightly in place by means of a cap 48 bolted as at 49 to the side of the preventer body. One of the caps 48 is provided with an opening therethrough to receive the outwardly extending portion of the shaft 35.

As best shown in FIGS. 1 to 4, there is a crank arm 55 releasably connected, as at 56, to the outwardly extending portion of each shaft 35, and an actuator 58 is pivotally connected at opposite ends to the outer end of each of the crank arms. The actuator 58 is extendible and re tractable, in a manner to be described hereinafter, so as to vary the distance between said ends of the crank arms 55 and thereby rotate the shafts 35 in a manner to move the rams 27 between opened and closed positions. Thus, with reference to FIGS. 3 and 4, it will be understood that when the actuator 58 is retracted the crank arms 55 will be moved to a position of FIG. 4 so as to close the rams and when the actuator 58 is extended the crank arms 55 are swung in a direction to open the rams. As best shown in FIGS. 3 and 4, each crank arm comprises a yoke having openings 57 through the outer ends thereof for releasable connection with the actuator 58 in a manner to be described below.

It will be seen from FIG. 4 that in the closed position of the rams the crank arms 55 form a substantial angle with respect to the horizontal so as to provide a relatively large moment arm for rotating the shafts during the start of the opening movement of the rams. For this purpose, the crank arms 55 may lag the interior crank arms 36 a certain amount, such amount to be governed by the overall rotative movement of the interior crank arms 36 between the position they assume in closing the rams and the position they assume in releasing the rams.

As best shown in FIG. 1, it is contemplated that one of the external crank arms 55 (the rightmost) is longer than the other. Thus, there will 'be more torque available for rotating the shaft 35 to which the longer arm is connected than for rotating the other shaft so the ram actuated by the longer arm and its shaft will be moved from closed position before the other ram. Since this initial movement of one of the rams releases the pressure differential across both rams, the other ram requires less torque for moving it to its open position. Therefore, this arrangement enables the power requirements of the actuator to be less than they would be if the crank arms 55 were of equal lengths totaling the length of the arms illustrated.

In the illustrative embodiment shown in FIGS. 1, 2 and 7 to 9, the actuator 58 comprises a piston 59 connected to one of the crank arms (the rightmost in FIG. 7) and movable within a cylinder 60 connected to the other crank arm 55 (the leftmost in FIG. 7). More particularly, the stem of the piston 59 is provided with a dependent support 61 and the cylinder 66 with a depending support 62, each having an opening therethrough to receive a pin 63 pivotally connecting said piston and cylinder to the crank arms 55. As shown in FIG. 8, the pin 63 is provided with a portion 64 threadedly received within one arm of the yoke making up crank arm 55, and its outer end is provided with a hammer lug head 65. Thus, when it is desired to remove the extendible and retractable actuator 53 from the crank arms 55, the head 65 upon each of the pins 63 may be given a hard blow to loosen the threads 64, whereupon the pin is easily and quickly removable frpm the yoke and the opening through the support.

As shown in FIG. 7, the cylinder 60 includes a first portion 66 which is closed at opposite ends to define a pressure chamber 67 therein and a second portion 68 extending longitudinally of the portion 66 above the piston 59. This second portion 68 is open along its lower side so as to accommodate movement of the support 61 on the piston 59. A piston head 69 on the stem of the piston 59 is sealably slidable Within pressure chamber 67 and conduits 70 and 71 are connected to the cylinder 60 for communication with the pressure chamber 67 at opposite sides of the piston head 69. Thus, the piston 59 may be reciprocated with respect to the cylinder by a suitable hydraulic system (not shown), in a manner well known in the art.

"As also shown in FIG. 7, a rod or locking screw 72 is received for rotation within the rightmost end 68a of the portion 68 of cylinder 60 and is held against longitudinal movement with respect thereto by means of an annular collar 6812 along an intermediate portion thereof. An inner threaded end 73 of the rod 72 extends within a hollowed out portion 74 of the piston stem, and the outer end thereof is provided with a non-circular part 75 to facilitate rotation of the screw for a purpose to be described.

A part 75a is received about the threaded inner end 73 of the rod and is provided with flanges 76 on each opposite side for sliding engagement over the open lower side of the portion 68 of the cylinder as shown in FIG. 9. Thus, upon rotation of the rod 72, the part 75a is moved longitudinally of the rod and cylinder and into and out of abutment with the outer end of the piston 59. When the piston and cylinder are in their retracted positions (FIG. 4), the part 75a may be moved into abutment with the piston so as to hold the rams in their closed position. On the other hand, it is contemplated that this locking screw may be used to move the ram from an opened to a closed position when, for example, there is a power failure in the hydraulic system for reciprocating the piston within the cylinder.

The operation of the blowout preventer of this invention is believed apparent from the foregoing description. Thus, for example, assuming a pipe 32 was disposed within the bore 21 of the preventer body and it was desired to close off the well about the pipe, hydraulic fiuid would be supplied through conduit 71 to the pressure chamber 67 behind the piston head 69 and withdrawn through conduit 70 from the pressure chamber in front of the piston head in order to move the piston 59 to its retracted position within the cylinder 60. This, in turn, would swing the exterior crank arms 55 to rotate the shafts 35 in directions for moving the rams to closed position. Since the internal crank arms 36 are swung by the shafts 35, it is not necessary for the power system to overcome any piston eifect.

When it is desired to open the bore of the preventer body about the pipe 32, hydraulic fluid is introduced into the pressure chamber 67 at the front of piston head 69 and withdrawn from the chamber behind the piston head to move the piston 59 to its extended position with respect to the cylinder 60. With the bonnets 23 closing the outer end of each guideway 22, the rams will thus be retracted into the open position.

When it is desired to replace one or both of the rams or parts thereof, one of the bonnets 23 is released and swung to its open position. The actuator 58 is at this time further extended to swing the crank arm 36 for the ram within the open guideway to a position in which the rollers 37 on the arm have forced the ram to a position in which its outer end projects from the outer end of its guideway. Further movement of the crank arm 36 will cause the rollers 37 to move through the opening from the lower side of the ram slot 38 so the crank arm 36 is disengaged from the ram. This disengagement of the actuator from the ram enables it to be moved manually to a position projecting still further from the guideway or completely removed from the guideway.

When the first ram has been replaced, the actuator is retracted so as to re-engage the rollers 37 within the slot 38 and return the ram to the position within the guideway. The bonnet 23 is then swung to its closed position and bolted to the body. At this time, the bonnet 23 at the other end of the body is released and swung to a position opening the other guideway whereby the other ram may be replaced in the manner above described. Obviously, upon replacement of one or more of the parts of the rams, they may be moved back into the guideways such that the crank arms may be engaged with the slots therein for moving them between opened and closed positions during normal operation of the preventer.

The form of actuator shown in FIGS. 10 and 11 is connected to the free swinging ends of the external crank arms 55 which are releasably connectible to the outer ends of shafts 35, as shown in FIGS. 1 and 2, by means of suitable clamps 97 or the like on their opposite ends. More particularly, this form of actuator includes a cylinder 98 having a first portion which is closed at its opposite ends by means of cylinder heads 99 and 100 to form a pressure chamber 101 therebetween and a longitudinal extension 102 on the first portion having a depending portion 103 forming a bearing for a pin 96 pivotally connecting the leftmost crank arm 55 to the cylinder. A piston 104 includes a head 105 sealably slidable within the pressure chamber 101 and a stem 106 connected at one end with the head 105 and extending through cylinder head 99 for connection with a body 107. The latter provides a bearing for another pin 96 pivotally connecting the piston to the rightmost crank arm 55.

Thus, as the piston and cylinder are retracted with respect to one another to move piston head 105 toward cylinder head 99, the crank arms 55 will be swung inwardly toward one another for moving the rams to closed position. On the other hand, as the piston and cylinder are extended with respect to one another to move the head 105 of the piston toward the'cylinder head 99, the crank arms 55 will be swung away from one another, as shown in FIG. 10, to move the rains to opened position. Additional extension of the piston and cylinder enables still further movement of the rams away from one another into a position from which they will be removed from their respective guideways in the manner previously described.

Ports 108 and 109 connect the exterior of the cylinder with the pressure chamber 101 for admitting and withdrawing hydraulic fluid to and from opposite sides of the piston head 105 for moving the piston and cylinder with respect to one another in an obvious manner. A bleed port 10801 connects with the interior of the chamber on the left side of the piston head 105. A rod 110 extends longitudinally of the piston and cylinder and is provided with a nut 111 at each end thereof for hearing against the outer sides of depending portion 103 and the cylinder head 100. As shown in FIG. 10, the rod 110 extends through the piston 106 to provide an annulus 112 which is closed at one end by the body 107 and at the other end by the piston head 105. More particularly, the annulus is filled with a suitable lubricant, and split rings 113 are received within a recessed portion 114 about the rod. As will be understood in connection with FIG. 11, the rings restrict the flow of lubricant therepast Within the annulus, during reciprocation of the piston with respect to the cylinder, so as to reduce the speed of such reciprocation. Lubricant may be introduced into the annulus 112 through either of the connections 115 or 116.

Another longitudinally extending rod 117 is freely carried within an opening 118 in the depending portion 103 of the cylinder extension for rotation and movement longitudinally with respect thereto. The outer end of this rod is provided with a non-circular part 119 for connection with a suitable tool for rotating same, and the inner end thereof is threaded at 120 for connection with a threaded opening 121 in the body 107 of the piston 104. Thus, the rod 117 may be rotated in opposite directions for moving the surface 122 on its inner end toward and away from the outer side of cylinder head 99. In this manner, the rod 117 can be manipulated to limit the extension of the piston and cylinder with respect to one another. More particularly, when the piston and cylinder are retracted so as to move the rams to closed position, the rod 117 may be turned to a position in which the surface 122 thereof engages with the cylinder head 99 to hold the rams in such position.

In the form of actuator 123 shown in FIG. 12, each of the pins 124 for pivotal connection with an external crank arm (not shown) is connected to a cylinder 125, each such cylinder having an inner cylinder head 126 and an outer cylinder head 127 to form a pressure chamber 128 therebetween. Pistons 129 are connected in spaced-apart relation on each end of a rod 130 for reciprocation within each of the cylinders whereby the cylinders may be extended and retracted with respect to one another for moving the pins 124, and thus the rams, toward and away from one another. Ports 131 and 132 are provided to connect the exterior of each of the cylinders with the interior thereof on opposite sides of the piston 129 so as to extend and retract the cylinders in a manner to be described.

The exterior portion of the rod as well as the seals between the rod and the cylinders 125 are protected against debris by means of an accordion-type cover 133 surrounding the rod and anchored at its opposite ends to the cylinder heads 126.

A hollow rod 134 is rotatably mounted within an opening 135 in the cylinder head 127 of the leftmost cylinder for extension longitudinally of the cylinders and rod 130. The outer end of the hollow rod 134 is provided with a non-circular part 136 to facilitate its rotation by a suitable tool, and the inner end thereof is provided with a threaded opening 137 for connection with the threaded inner end of another rod 138 anchored at its outer end to the cylinder head 127 of the rightmost cylinder by means of a pin 139. The outer end of the hollow rod 134 is also provided with a collar 140 which is adapted to bear against the head 127 of the leftmost cylinder 125 so that, as the hollow rod is rotated in one direction, the cylinders 125 are forced toward one another. Thus, when the rams have been moved to closed position by retraction of the cylinders with respect to one another, the hollow rod 134 may be rotated in said one direction to move the enlargement 140 inwardly into engagement with the head 127 on the leftmost cylinder for locking the rams in such position.

The rod 130 connecting the pistons 129 is made up of two concentrically arranged tubular parts 141 and 142 which form an annulus 143 therebetween. Ports 144 in the outer part 141 connect the pressure chambers on the inner side of each of the pistons with one another through the annulus. On the other hand, the pressure chambers on the outer side of such pistons are connected by the annulus formed between the inner tubular part 142 and the outer diameter of the rod 134. Thus, hydraulic fluid may be introduced and withdrawn to and from the chambers through only one pair of ports 131 and 132, and the other ports may be plugged as shown in FIG. 12.

In the form of actuator 145 shown in FIG. 13, the external crank arms 55 are pivotally connected to tubular members 147 and 148, respectively, by means of pins 146. The member 147 is guidably reciprocable within the tubular member 148, and a rod 149 is carried by the outer tubular member 148 for extension longitudinally of both members and rotation with respect to the outer tubular member 148. The inner end of this rod is threaded at 150 for connection with a threaded opening 151 in the inner end of inner tubular member 147. The outer end of the rod 149 is provided with a collar 152 which is held between bearings 153 and 154 housed within the outer tubular member so as to be fixed against movement longitudinally with respect thereto. Thus, as the rod is rotated by means of a non-circular part 155 on its outer external end, the inner and outer tubular members are caused to be extended and retracted with respect to one another for moving the rams between the designed positions.

As in the case of the form of actuator shown in FIGS. 10 and 11, the inner fixed ends of the crank arms 55 may be releasably connected to a shaft, such as shown at 35 in FIGS. 1 and 2, by means of clamps 156.

Obviously, each of the actuators shown in FIGS. 10 to 13 may be manipulated, in the manner described in connection with the actuator of FIGS. 7 to 9, to move the rams between opened and closed positions and another position for replacement.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claim.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed A blowout preventer, comprising a body having a bore therethrough and a pair of guideways therein intersecting the bore, a ram longitudinally movable within each of the guideways, a pair of shafts mounted on the body for rotation about an axis transverse to the direction of movement of each of said rams, means connecting an inner portion of each shaft to one of the rams for moving said rams between bore opening and closing positions, a crank arm on each shaft exteriorly of the body, and an extendible and retractable actuator removably and pivotally supported on the exterior crank arms for rotating the shafts in directions to move the rams between opened and closed positions.

References Cited by the Examiner UNITED STATES PATENTS 131,135 9/72 Thompson 92-66 678,150 7/01 White 92-66 893,770 7/08 Wilson 251239 X 1,809,230 6/ 31 Bettinger 277-127 1,834,922 12/ 31 Abercrombie 277 127 X 1,891,570 12/32 Nelson 251-1 2,132,037 11/3 8 Mac Clatchie 277-127 2,146,470 2/39 Grantham 2511 2,282,363 5/42 King 277127 ISADOR WEIL, Primary Examiner. 

